Fix iovec size for MIPSn32.

kernel/src/syscall/fs.rs

@@ -1074,6 +1074,9 @@ pub struct IoVec {
     /// Starting address
     base: *mut u8,
     /// Number of bytes to transfer
+    #[cfg(target_arch = "mips")]
+    len: u32,
+    #[cfg(not(target_arch = "mips"))]
     len: u64,
 }
 

kernel/src/syscall/mod.rs

@@ -319,6 +319,9 @@ pub fn syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> isize {
 #[cfg(target_arch = "mips")]
 fn mips_syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> Option<SysResult> {
     let ret = match id {
+        SYS_OPEN => sys_open(args[0] as *const u8, args[1], args[2]),
+        SYS_DUP2 => sys_dup2(args[0], args[1]),
+        SYS_MMAP2 => sys_mmap(args[0], args[1], args[2], args[3], args[4], args[5] * 4096),
         SYS_SET_THREAD_AREA => {
             extern "C" {
                 fn _cur_tls();